1. Field of the Invention
The invention relates to enhanced mounting hardware for a circuit board, and in particular, to an enhanced mounting arrangement for securing a component, such as a module, to a circuit board.
2. Background Information
Circuit boards, such as those used in computers, for example, typically have various components, such as processor and memory modules connected to a surface thereof. The circuit boards are usually connected to a further circuit board, commonly referred to as a backplane, for example. The assembly of the backplane and the various circuit boards may be positioned within an open cage, which is a frame fixed within a computer housing. The cage serves to position the circuit boards within the computer housing.
Typically, the modules are connected to the circuit board in a permanent relationship by soldering the modules directly to the circuit board. This type of connection is a concern because of the reliability of the solder connection. For example, a poor electrical connection between devices may occur if the solder joint is too small, the solder joint has too much flux, or the solder joint is cracked. In addition, this type of permanent connection disadvantageously prevents the modules from being easily removed from the circuit board for repair or replacement purposes.
Alternatively, the modules can be connected to the circuit board using a pin-and-socket connector. However, this type of connection disadvantageously results in a relatively high impedance. As is known to those skilled in the art, a high impedance is undesirable, since this may reduce the signal strength between the circuit board and the associated module.
It is also known to use a so-called array connector in order to connect the modules to a circuit board. Such connectors typically include a relatively small, flat panel having a relatively large number of conductive pads formed thereon. The array connector is positioned between the circuit board and the associated module, with the conductive pads of the array connector being in registration with a like number of corresponding conductive pads located on both the circuit board and the module. The conductive pads of the array connector thus causes an electrical connection between conductive pads on the circuit board, and the module. In order to ensure an electrical connection between the circuit board and the module, the conductive pads of the array connector must be property aligned with the corresponding conductive pads of both the circuit board and the module. Moreover, a relatively large force needs to be applied. For example, a typical minimum force for a gold-to-gold contact is approximately 0.1 pound-per-contact. Therefore, for an exemplary array connector with 1024 conductive pads (i.e., contacts), a minimum force of approximately 110 pounds should be applied to hold the array connector between the circuit board and the module.
Typically, this force is generated through the use of a relatively large, expensive, complicated arrangement of springs and screws which are positioned at each of the four corners of the array connector. This type of arrangement disadvantageously has numerous separate parts. Thus, the known arrangement for securing an array connector to a circuit board may be difficult to use, due to its complexity. Further, access to the springs and screws of the known arrangement may be limited, which is disadvantageous because the modules may need to be replaced or upgraded, on occasion. Therefore, there is a need for an arrangement for securing an array connector between a circuit board and a module, that is easy to use.
Further, the known arrangement makes it difficult to align the conductive pads of the array connector with the conductive pads of the circuit board and module. Thus, there is a need for an arrangement in which the conductive pads of the circuit board, module, and array connector (if provided) can be easily and precisely aligned.
In addition, during operation, the various electrical components located on the circuit boards, for example the processor modules, tend to consume a substantial amount of electrical power, and therefore tend to generate a substantial amount of heat. Because excess temperature can impair a computer system's reliability and functionality, the modules are often provided with heat sinks to help dissipate the generated heat. On some circuit boards, the heat sinks are provided in such a high density that nearly the entire surface of the circuit board is covered by heat sinks. Therefore, space is often at a premium, and the above-described arrangement of the springs and screws may not be feasible with certain circuit boards. Thus, there is a need for an arrangement that it is suitable for holding a module to a circuit board, even when the heat sinks are densely arranged.
Additionally, the conductive pads of the array connector will typically compress due to the applied force over a period of time. In the conventional arrangement, this will result in a reduction in the applied force, which may ultimately result in the electrical connection between the circuit board and the module failing. Thus, there is a need for a way to apply the necessary force to an array connector which will not diminish over time.